Preparation

Combine onion powder, garlic powder, black pepper, ground red pepper and thyme in small bowl. Rub spice mixture onto both sides of tuna. Place tuna on broiler pan. Broil 4 inches from heat about 10 minutes or until of desired degree of doneness, turning halfway through broiling time. Cover and set aside.

For dressing, bring water to a boil in small saucepan over high heat. Add onion slices; reduce heat to medium-low. Simmer, covered, 4 to 5 minutes or until onion is tender. Add vinegar, mustard, oil and bouillon granules; cook and stir until heated through.